Bonjour

Bonjour, also known as zero-configuration networking, enables automatic discovery of devices and services on a local network using industry standard IP protocols. Bonjour makes it easy to discover, publish, and resolve network services with a sophisticated, easy-to-use programming interface that is accessible from Cocoa, Ruby, Python, and other languages.

Bonjour for Windows

Source Code and Specifications

Bonjour is not only based on open Internet standards, our implementation is also available as Open Source under the Apache 2.0 license. It is built into most modern printers and many other consumer products.